#21C4E8
Closest named color: Vivid Sky Blue (#4CC9F0). oklch(75.9% 0.131 218.1), rgb(33, 196, 232).
Aa
Black text reads best on this color (10.12:1).
About this color
#21C4E8 is a medium-light, moderately saturated teal or cyan. In OKLCH its lightness is 76%, its chroma 0.131 and its hue 218°. Its hue sits on the cool side of the wheel. The nearest named color is Vivid Sky Blue (#4CC9F0), ΔE 0.027 away. Black text reads best on it, at 10.12:1.
| Hue family | Teals and cyans |
| Lightness | medium-light (76%) |
| Chroma | moderately saturated (0.131) |
| Temperature | cool |
| Nearest name | Vivid Sky Blue (#4CC9F0) |
| Black text | 10.12:1 |
| White text | 2.07:1 |
Values
| HEX | #21C4E8 |
| RGB | rgb(33, 196, 232) |
| HSL | hsl(191, 81%, 52%) |
| OKLCH | oklch(75.9% 0.131 218.1) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #21C4E8 | 2.07:1 | Fails | Lc -44.5 | Non-text elements, placeholder text |
| Black text on #21C4E8 | 10.12:1 | AAA | Lc 64.0 | Content text, not long reading |
| #21C4E8 text on white | 2.07:1 | Fails | Lc 40.0 | Non-text elements, placeholder text |
| #21C4E8 text on black | 10.12:1 | AAA | Lc -62.4 | Content text, not long reading |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 300.
-
Step 50
50
#E9F9FD
oklch(97.1% 0.018 214.4)
-
Step 100
100
#CFF1FB
oklch(93.7% 0.038 217.4)
-
Step 200
200
#A2E5F9
oklch(88.4% 0.072 218.4)
-
Step 300
300 (this color)
#21C4E8
oklch(75.9% 0.131 218.1)
-
Step 400
400
#00B3D5
oklch(70.8% 0.127 217.9)
-
Step 500
500
#0099B7
oklch(63.1% 0.114 218.3)
-
Step 600
600
#00819A
oklch(55.7% 0.1 217.7)
-
Step 700
700
#006C82
oklch(49.1% 0.088 218.4)
-
Step 800
800
#00596B
oklch(42.8% 0.077 217.7)
-
Step 900
900
#004A59
oklch(37.7% 0.067 217.2)
-
Step 950
950
#002C36
oklch(27% 0.048 217.4)
#21C4E8 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #ADBEEA | 0.112 |
| Deuteranopia (no green cones) | #94ACE8 | 0.100 |
| Tritanopia (no blue cones) | #00D0CF | 0.057 |
| Achromatopsia (no color) | #B4B4B4 | 0.132 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21C4E8
#21C4E8
oklch(75.9% 0.131 218.1)
- #F79272
#F79272
oklch(75.9% 0.131 38.3)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #21C4E8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Vivid Sky Blue #4CC9F0 ΔE 0.027
- Bright Sky Blue #02CCFE ΔE 0.034
- Deep Sky Blue #00BFFF ΔE 0.040
- Dark Turquoise #00CED1 ΔE 0.051
- Aqua Blue #02D8E9 ΔE 0.056
- Lightblue #7BC8F6 ΔE 0.063
- Medium Turquoise #48D1CC ΔE 0.065
- Turquoise Blue #06B1C4 ΔE 0.068
Use #21C4E8 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.